Absorbent articles such as diapers, training pants, incontinence products, feminine hygiene products, swim undergarments, and the like conventionally include a liquid permeable body-side liner, a liquid impermeable outer cover, and an absorbent core. The absorbent core is typically located in between the outer cover and the liner for taking in and retaining liquids (e.g., urine) exuded by the wearer.
The absorbent core can be made of, for instance, superabsorbent particles. Many absorbent articles, especially those sold under the tradename HUGGIES™ by the Kimberly-Clark Corporation, are so efficient at absorbing liquids that it is sometimes difficult to tell whether or not the absorbent article has been insulted with a body fluid.
Accordingly, various types of moisture or wetness indicators have been suggested for use in absorbent articles. The wetness indicators, for example, may include alarm devices that are designed to assist parents or attendants identify a wet diaper condition quickly upon insult. The devices produce either a visual or an audible signal.
In some embodiments, for instance, inexpensive conductive threads, foils, or paper have been placed in the absorbent articles in the machine direction. The conductive materials serve as conductive leads for a signaling device and form an open circuit in the article that can be closed when a body fluid, such as urine, closes the circuit. In these embodiments, although the absorbent articles may be disposable, the signaling devices are not. Thus, the signaling devices are intended to be removed from the article and reattached to a subsequent article.
Incorporating conductive leads into absorbent articles, however, has caused various problems. For example, absorbent articles are typically mass produced on very fast moving machinery. Incorporating conductive leads into an absorbent article at conventional machine speeds has been problematic.
In addition, packaged absorbent articles are typically fed through a metal detector to ensure that there are no foreign objects contained in the package. If the conductive leads are made from or contain a metal, the metal detector can be activated registering a false positive. The incorporation of metallic materials into absorbent articles can also cause problems for those wearing the garments when attempting to pass through security gates that include metal detectors.
Several technologies have enabled wetness detection with little to no product alteration using non-invasive sensors that can be removably placed on the absorbent article. By way of example, U.S. Patent Application Publication No. 2010/0168694, which is incorporated herein by reference for all purposes, discloses an infrared wetness detection system for an absorbent article that includes a non-invasive sensor that measures infrared reflectance at some depth within an absorbent article. U.S. Patent Application Publication No. 2010/0164733, which is incorporated herein by references for all purposes, discloses the use of various sensors, such as a temperature sensor, a conductivity sensor, a humidity sensor, a chemical sensor, a vibration sensor, or a material expansion sensor placed on an outside cover of an absorbent article. U.S Patent Application Publication No. 2009/0124990, which is incorporated by reference herein for all purposes, discloses the use of an induction coil sensor for wetness detection in an absorbent article. Commonly owned U.S. patent application Ser. No. 12/648,645, which is incorporated herein by reference for all purposes, discloses a non-invasive capacitive sensor system and associated circuitry for wetness detection. In these embodiments, complexity falls to the signaling devices attached to the absorbent articles.
While a non-invasive signaling device provides many advantages, problems can be encountered in properly associating a particular signaling device with a proprietary product. In particular, due to the non-invasive nature of such signaling devices, a proprietary signaling device can be used with any absorbent article, regardless of the manufacturer or source of the absorbent article. Moreover, non-invasive signaling devices can be used on products that have not been safety cleared for use with a signaling device.
Thus, a need exists for an apparatus and method that enables product and signaling device matching for use.